We synchronize all threads each RAM_SAVE_FLAG_EOS. Bitmap
synchronizations don't happen inside a ram section, so we are safe
about two channels trying to overwrite the same memory.
Signed-off-by: Juan Quintela <quint...@redhat.com>
---
migration/ram.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
migration/trace-events | 3 +++
2 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/migration/ram.c b/migration/ram.c
index 6aeb63f6ef..4ba03cf9c9 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -565,6 +565,7 @@ struct MultiFDRecvParams {
QemuMutex mutex;
bool running;
bool quit;
+ bool sync;
};
typedef struct MultiFDRecvParams MultiFDRecvParams;
@@ -572,6 +573,8 @@ struct {
MultiFDRecvParams *params;
/* number of created threads */
int count;
+ /* syncs main thread and channels */
+ QemuSemaphore sem_main;
} *multifd_recv_state;
static void multifd_recv_terminate_threads(Error *errp)
@@ -618,6 +621,7 @@ int multifd_load_cleanup(Error **errp)
g_free(p->name);
p->name = NULL;
}
+ qemu_sem_destroy(&multifd_recv_state->sem_main);
g_free(multifd_recv_state->params);
multifd_recv_state->params = NULL;
g_free(multifd_recv_state);
@@ -626,19 +630,59 @@ int multifd_load_cleanup(Error **errp)
return ret;
}
+static void multifd_recv_sync_main(void)
+{
+ int i;
+
+ if (!migrate_use_multifd()) {
+ return;
+ }
+ for (i = 0; i < migrate_multifd_channels(); i++) {
+ MultiFDRecvParams *p = &multifd_recv_state->params[i];
+
+ trace_multifd_recv_sync_signal(p->id, p->quit, p->running);
+
+ qemu_mutex_lock(&p->mutex);
+ p->sync = true;
+ qemu_mutex_unlock(&p->mutex);
+ qemu_sem_post(&p->sem);
+ }
+ for (i = 0; i < migrate_multifd_channels(); i++) {
+ MultiFDRecvParams *p = &multifd_recv_state->params[i];
+ bool wait;
+
+ trace_multifd_recv_sync_wait(p->id, p->quit, p->running);
+
+ qemu_mutex_lock(&p->mutex);
+ wait = p->running;
+ qemu_mutex_unlock(&p->mutex);
+
+ if (wait) {
+ qemu_sem_wait(&multifd_recv_state->sem_main);
+ }
+ }
+ trace_multifd_recv_sync_main();
+}
+
static void *multifd_recv_thread(void *opaque)
{
MultiFDRecvParams *p = opaque;
while (true) {
+ qemu_sem_wait(&p->sem);
qemu_mutex_lock(&p->mutex);
+ if (p->sync) {
+ p->sync = false;
+ qemu_mutex_unlock(&p->mutex);
+ qemu_sem_post(&multifd_recv_state->sem_main);
+ continue;
+ }
if (p->quit) {
p->running = false;
qemu_mutex_unlock(&p->mutex);
break;
}
qemu_mutex_unlock(&p->mutex);
- qemu_sem_wait(&p->sem);
}
return NULL;
@@ -656,6 +700,7 @@ int multifd_load_setup(void)
multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
atomic_set(&multifd_recv_state->count, 0);
+ qemu_sem_init(&multifd_recv_state->sem_main, 0);
for (i = 0; i < thread_count; i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
@@ -2890,6 +2935,7 @@ static int ram_load_postcopy(QEMUFile *f)
break;
case RAM_SAVE_FLAG_EOS:
/* normal exit */
+ multifd_recv_sync_main();
break;
default:
error_report("Unknown combination of migration flags: %#x"
@@ -3075,6 +3121,7 @@ static int ram_load(QEMUFile *f, void *opaque, int
version_id)
break;
case RAM_SAVE_FLAG_EOS:
/* normal exit */
+ multifd_recv_sync_main();
break;
default:
if (flags & RAM_SAVE_FLAG_HOOK) {
diff --git a/migration/trace-events b/migration/trace-events
index 845612c177..551d325daf 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -80,6 +80,9 @@ ram_save_queue_pages(const char *rbname, size_t start, size_t
len) "%s: start: 0
multifd_send_sync_main(void) ""
multifd_send_sync_signal(uint8_t id, bool quit, bool running) "channel %d quit
%d running %d"
multifd_send_sync_wait(uint8_t id, bool quit, bool running) "channel %d quit
%d running %d"
+multifd_recv_sync_main(void) ""
+multifd_recv_sync_signal(uint8_t id, bool quit, bool running) "channel %d quit
%d running %d"
+multifd_recv_sync_wait(uint8_t id, bool quit, bool running) "channel %d quit
%d running %d"
# migration/migration.c
await_return_path_close_on_source_close(void) ""
--
2.14.3
